Neoprene-phenolic adhesive cement



peratures will develop bond strength in the early stages at least about as rapidly as will a reclaimed rubber. limed rosin solvent-type cement, of the type described in Zimmerli et al. U. S. Patent No. 1,937,861; and further characterized in that after curing at room temperatures for three days will have a bond strength of about twice that of such a Zimmerli cement; and still further characterized in that after curing or ageing at such temperature for one to two weeks will have a bond strength of three to four times that of such a Zimmerli cement after a similar amount of curing. A further ancillary object of my inveny tion is to provide an adhesive composition of the' solvent type in which the neoprene polymer and the phenol aldehyde resin are uniformly blended and dissolved, as distinguished from composi tions in which the neoprene is dispersed in'a' These andotherjv f neoprene herein, it will be understood that I thereby refer to polymerized chloroprene 'and also to polymers of chloroprene with quite minor proportions of other monomers such as isoprene,

butadiene, and acrylonitrile or the like, so long as the final polymers have the usual neoprene properties Well-known in ordinary neoprenes of commerce (e. g. high insolubility in ordinary gasoline and incapability of being vulcanized with ordinary sulphur vulcanizing agents for ordinary rubber).

The adhesive cements of this invention are to be broadly distinguished from such polymerized chloroprene compositions as have heretofore been employed in cement form in adhering leather, fabric and similar porous and brous materials to themselves and to each other, as in the shoe industry. Such prior polymerized chloroprene cements have, in general, been ineffective in securing fabrics or other elements to non-porous surfaces such as smooth metal surfaces, because of lack of tack and adhesion. The dried residues obtained from such prior cements have generally been thermo-plastic and of a weakly adherent nature, and generally depend upon a mechanical interlocking with thefibers of a fibrous sheet, or the like, in order to form an effective bond. Ordinarily certain thermoplastic resins are used, in W percentage proportion, with neoprene in forming such cements.

By employing certain types of phenol aldehyde resins, in certain ranges of proportions as hereinafter set forth, with neoprene I have found thatI can produce a class of adhesive cements having characteristics and advantages which are new and unique over anything heretofore known to me, In general I have found that I should employ a phenol aldehyde resin consisting of the condensation product of a phenol substituted in the para position by a side chain radical containing at least three carbon atoms (and preferably atleast four carbon atoms) and an aldehyde of a saturated aliphatic alcohol. In order that the phenol aldehyde resin be of the desired reactive type the aldehyde should be present in excess of about a 1 to 1 molecular ratio, in relation to the phenol, and the condensation reaction (to produce the phenol aldehyde resin) should be carried out in the presence of an alkaline catalyst, e. g. NaOH, KOH, NH4OH, NazCOa, etc. The condensation reaction is not carried to completion, leaving the resin of intermediate molecular size; but the condensation reaction is carried far enough to provide a solid resin, at ordinary room temperatures. The phenol should have only two particularly reaction favorable positions in the molecule unoccupied. Examples of such a phenol are para-tertiary butyl phenol, para-tertiary amyl phenol, para-phenyl phenol and para-octyl phenol. Examples of a suitable aldehyde of a saturated aliphatic alcohol are formaldehyde and acetaldehyde.

. The excess of aldehyde, e. g. formaldehyde, over a 1 to 1 molecular ratio of aldehyde to phenol is usually such as to give a molecular ratio of aldehyde to phenol within the range of 1.2 to 1 up to 1.6 to 1," although there can be variations from k.this range, so. long as a molecular excess of the aldehyde over the phenol is employed, to provide a suitably reactive phenol aldehyde resin.

In respect to proportions of such a phenol alde- "hyde resin to neoprene I have found that the phenol aldehyde resin should be present to an extent by weight in excess of one-half that of the neoprene and, at the otherendof the range, should not be vpresent to a greater extent thann 11/2 to 2 times that of the neoprene. My preferred compositions have the phenol aldehyde resinv present tothe extent by weight of -90% of the neoprene. Where the proportion of the phenol aldehyde resin to the neoprene is reduced below about 60%, I find that the bond strength of the resulting cement begins to fall off quite noticeably. so that compositions where the phenol aldehyde resin is present to the extent of less than half that of the neoprene become quite inferior in bond strength, andit is desirable not to let the proportion of the phenol aldehyde resin drop below about 55% by weight of the neoprene. For most commercial uses I have found that my adhesive cements can best be made with the phenol aldehyde present in the range of to 85%, by weight, of the neoprene.

My invention will now be more specifically illustrated by giving a few illustrative embodiments or examples thereof.

EAMPLE 1 Part A.-PoZg/chlmoprene base .l Parts by weight Polychloroprene. (neoprene) 500 Phenyl alphanaphthylamine (antioxidant) 10 ,Extra light calcined magnesia 20 Zinc oxide 25 Mill the polymer on a rubber mill until it forms a continuous sheet around the roll. Add the antioxidantand magnesia, and finally the zinc oxide. `'Remove from the mill, and cut into convenient size pieces for dissolving.

base stock, in the toluol in a churn type mixer.

, Neoprene Type CG is a preferred polychloroprene or neoprene polymer. However, other types .of chloroprene polymers, such as Neoprene Type E or Type GN, may also be used. In general neoprene polymers are preferred which (in the amonio absence of milling) havearelativelyihigh durometer-hardnessva1ue-` y :1A good commercial yexample ofthe phenol 'aldehyde resin above; given is` SuperfBeckacite #1003, a product of Reichhold',Chelnicals, Tnc., Ferndale, Michigan. Itv isa -100%,1phenclform aldehyde resinproduced by condensing inlexcess of 1 ym01 of formaldehydewith v1.mo1..of para.- tertiary butyl phenol,'in the presence ofan alka.- line'catalyst,l to provide a resin, solid L.atc/room temperatures -(e.L g. melting, when first. heated, at-155 .to 18`0F.) and solublelin alcohols, ace:- tates, coal tar solvents, turpentine Yand dryingoils. The molratio .of'formaldehyde to phenolbisg in general, betweeny 1:1 and2:1,and about 1.5 tol is an example cfa-good ratio. The phenolic resins of the type aboveadesc'ribed contribute. both adhesion'r andY internal strength to thedried: residue ,ofi .myrv adhesive: cements; Surprisingly high internal v strengthr is lobtained merely'iby completeelimination of solventlfrom my cement at ordinary room temperatures. It has a wet strength, immediately after bonding, of the same orderas that oft az-immerli type cement, but upon continued ageing, it will'. soon exceed a film of Zimmerli cement in strength; .and following the elapse of .three days 'after application as a iilm or coating,` it willihave a'bond strength about twice asgreat as `that `of aiilm of a Zimmerli cement. Furtherincreasesin bond strength is secured. (perhapscbyre'action, or `further reaction, of the phenolic .resinwiththeneoprene polymer)y by furtherageingfat yroom temperature, with .the result thatfuafter curing-for one to two weeks, it has a bond .strength three or four timesithat cfa Zimmerli cement Y aslherein` above identied). i EXAMPLEQ u Part A.-Pol'ychloroprene base* Parts by weight Polychloroprene (i. e. neoprene) 500 Phenyl alpha naphthylamine (antioxidant) l Mill the neoprene polymer on a' rubber mill u'n-v tilit forms a continuous sheet around the roll.

Add the antioxidant. Then remove from the mill and cut in to convenient size pieces for dissolving..

Part B Cementv A ylfarts-byweight Base stock as prepared inpart A 100 Para-tertiary.amy1plienolformaldehyderesv in f85 Benzol 350 Dissolve `the resin, then the freshlyl prepared base stock, in the benzol on 'a churn' typeA mixer. The adhesive composition of Example 2V yis suitable for use as a clear weather-strip adhesive Onpainted surfaces, -where anyexcess of adhesive must not-show. l It developswet strength rapidly and, after a-few days ageing, tenaciously holds even highly plasticized sponge-rubber weatherstrip to4 enameled or lacquered .surfac'zes` 7 EXAMPLE 3 APartV A.-Polychloroprene basa Parts by weight Polychlorop-rene (neoprene) v `500I Phenyl alpha -gnaphthylamine (antioxia` dant) l .10 Extra light calcined rnagnesia A 20 Zinc4 oxide 25 oxidant, preferred in all. examples, iinprlov The adhesive.composition'ofExample3is su; able for use where aliigh' degree v of ilexib "ty is` required, for examplein laminating." sheets (as anon-slip surfacing) vti'ifaluxni aircraft vvings'. s f Y The; composition `of' Example l,ihowev'er." been more commonly usedfto bondthe v`bac non ga'brasive'side, Iof abrasive coated sheet rial to a metal .surface, e'.` g; a; rigdme port, a battleship deck`stone1oi" concrte st etc. but 'ai bondl formed with Vthe compli'sit 'n f Examplev provides somewhatlgreate'r'fleiib yl of'bond', where suchis desired.A i

The 'composition 'of'Example;js'cdiiiers'V from, that vofExample 1 in that alQWQLpeicentQe of the phenol-aldehyde yresi'nis employ d`f ample'' than in Example 1. Alsojit willbe that Va4 vspecifically diiferent A'phenol,-aldehyde resin, but of the ,particular ltype' hereinabove, del scribed,.is employed. Q v l It willjfurther be seen that'zafmodiedcgpentale' erythritol ester of polymerized rosin'is}.employ df in'lieu vof the. coumarone-indenelresin Ei:-4v amplel. f.

f Example 2 Sdiiers from both of Exampl 3 in that theonly solids vingredient:which itncozfi` tains inaddition to thevneoprene polymerfad ph'enol-aldehyde is Athe antioxidant. Thearitil the. ageiriglife of the neoprenepolymenj andiesists embrittlement due to oxidation.

As illustrated'by Example 2,',thefotherjaddi-ltional ingredients of Examples 1, and S'a essential to the broader aspects of my'i'nv` tign., However, they have been found to ,provide some.,` additional advantages, vunder various]circiiii-f stances, and'h'ence the use of themlforfsimilar. materials, is usually preferred.. The magnesia., for example, shownboth in .EXaniplsl 1` antilla, is desirable where the adhesive 'cementisjtofbe employed incontact with cloth or metal''r other. materials affected by an acid condition. Itgis, normal in the ageing of neopreneior. amounts of hydrochloricfacid to be formedlffllhe calcined magnesia serves as a suitableacidaci-j cept'or and is nt'otherwise harmfltoth position; Both magnesium oxide'a'nd zinccnnle,y the latter also being'shown in Examples 1 and 3 are commonly used in many' neoprene' compost# tions and give vcertain well appreciatedadvan'- tages;` However,`it` is believed that these'irr`-'f gredients have-some additional, or special.'v adef vantages in'my adhesive cement compositions, and may serve to catalyze a reaction*betweenv the neoprene polymer and the phenol-aldehyde resin" during ageing atroom temperatures. i'-VS-liil'e'fsu'cli catalyzing action is not essentialto the-1develop ment of quitev high bond strengtl'is,` `the'.f'pr'esencev eht ma indene resin or like thermoplastic resin compatible with the neoprene. While such a compatible thermoplastic resin is not essential, as illustrated in Example 2, yet when employed, for example, in quantities of the general order illustrated in Examples 1 and 3, it has the effect of causing the solvent to be -released more rapidly from the adhesive cement when applied as a 111m or coating in use, therebyaiding the cement to more rapidly develop Wet strength. What may be the mechanism of this effect is not known, but, in general, high melting point thermoplastic resins compatible with neoprene, employed in any proportion up to about 30% or 4.0% of the neoprene polymer, functions to improve the rate at which bond strength will developin a film or coating, following application of the cement to asurface in use. Additionally,fsuch a thermoplastic resin has been found to'improve the shelf life, or can ageing life, of myjadhesive cement compositions. By way of illustration,` a'cement as shown in Example 1 has a can ageing life of at least one year, whereas a similar cement, except for replacement of the thermoplastic resin with corresponding amount of-phenol-aldehyde resin, has its can life reduced to about three months, or perhaps even to about two months. Such a can ageing life, however, is still adequate for many uses.

The particular coumarone-indene used in Example 1 was a light colored grade having a melting" range ofV 15G-160 C. The thermoplastic resin of Example 3 (i. e. the modified pentaerythritol ester of polymerized rosin) had a melting range of about 1Z0-125 C. Lower melting point resins appear to be less effective in releasing the solvent from my adhesive cements in film form; although' somewhat lower melting point thermoplastic resins which are compatible with neoprene can be employed to some advantage. The adhesive cements of this invention may advantageously vbe employed for many difficult cementing and adhesive uses. For example, they may be employed in permanently adhering abrasive coated sheets or strips to metal decks, to provide` a non-skid surfacing material thereon. The non-skid sheeting may consist of an impregnated cloth base carrying a surfacing coating of mineral or abrasive grains bonded to the base with a resinous binder. My adhesive cement solution may be applied, as by brushing, on either or both of the surfaces which are to be joined together. The solvent will be eliminated by evaporation. By allowing some evaporation of solvent before the bond is made, the bond strength of the coating will develop more rapidly. i Such non-skid treads'have been bonded effectively with `my' adhesive cement to such varied surfaces as smooth steel, aluminum, and painted woodsurfaces, as well as to concrete and masonry surfaces. 'I'he bonds produced were exceptionally strong and tough, and were highly resistant to, heat, solvents, oil, oxygen and moisture. My cements have also been employed to bond sponge rubber strips to metal and plastics, as a weatherstrip material; to adhere a cotton covering on the decks of ships; to impregnate and bond glass cloth to the surface of pipes to serve as a re resistant insulation; to'adhere vinyl resin sheeting to itself and to metals; to serve as'ja binder in the manufacture of brake 1inings; to fasten` rubber cushions to plastics in the manufacture of radios; to bond linoleum trim to aluminum in railroad car manufacture; to fasten rubber to glass in making double pane Windows;`

and to permanently bond formica table tops to metal and wood underlying surfaces. My ladhesive cements have many other uses and their meritis especiallyevident where a permanent adhesive isrequired having an exceptionally high bondstreng'th and/or where the bond is to be between (o1`- to) materials or under conditions Where it .would be inconvenient, expensive or impossible to. heat the cement film l in situ. There'are a number of usages, such as various of those above illustrated, where a Zimmerli type cement as hereinabove identified, d'oes not provide a bond of sufficient strength under the various conditions encountered'in usage sov as to provide an acceptable' adhesive. My cements provide a differentand much higher order of bonding strength.

As an illustration of the strength of bonds v prepared by the adhesive cements of this invention, two sets of specimens were prepared, by

brushing liquid adhesive cement or composition to be tested on a steel panel, pressing a fabric strip in place thereon and allowing the composite to dry and age at room temperature for two weeks. One set of the specimens was prepared by using the adhesive of Example 1 hereof. The other set of specimens was prepared using a Zimmerli type adhesive. On a strip back test of the two sets of specimens, conducted by stripping the fabric back on itself on a tensile test Y machine operating at a jaw separation speed of two inches per minute. and expressing the results in pounds per inch of width of the strip tested, the specimens formed with the cement of this invention showed a strip back value of 43 lbs. per inch, whereas the specimens formed with the Zimmerli cement showed a strip back value of approximately 8 lbs. per inch of width.

Another set of specimens was similarly prepared except that the adhesive cement employed was made in accordance with the following formula:

- Grams Rubber (smoked sheet) Phenol-aldehyde resin (same as in Example l hereinabove) 100 Toluol 400 The specimens made by coating the adhesive cement iust indicated (which is similar to that shown in Bitterich U. S. Patent No. 2,211,048). and also curing simply at room temperatures for two weeks. showed strip back values of approximately 3.5 lbs. per inch of width (even lower than the Zimmerli type cement). It is, of course, true that if the last mentioned specimens were heated in situ, e. g. at temperatures of about -180C., as recommended in the Bitterich patent, substantial increases in bond strengthv would occur.

In place of toluol or benzene, as illustrated in the examples given above, I may employ as my solvent various aromatic hydrocarbons, chlorinated hydrocarbons and petroleum solvents containing high percentages of aromatic or naphthenic constituents, as well as other suitable volatile solvents in which the ingredients of my cement compositions are soluble to give the cement a suitable consistency, for example as hereinabove illustrated.

Where desired, various pigments, inert fillers, (granular or fibrous) or coloring materials may be added to any of my cement compositions. Fibrous material such as asbestos fibers are advantageous in some uses, e. g. to reduce the flow of aeratio- 9 the wet cement whenl applied in thick layers, as inicovering metaltto metal joints, andsuch like..

' While my inventionhas been describedin various-details and various examples given, it will be understoodthat these- 'are `for v,purposes of illustration v`and :that all'4 embodiments within the scope of my invention as 'herein .described or claimed are comprehended. 'A y "WhatIclaimis:

1.*A'solvent type adhesive cement composition whichis resistant toigelation insolution during storage, and upon application asar coating to impervioussmooth metal surfaces forms'a strongly adherent iilm of'high internal strength on mere evaporation of solvent andbriefageing at normal room temperatures, said composition,comprisingr a' uniform blend of ypolychloroprene and a 'normally solid phenol-aldehyde resin, `said blend beingY dis.- solved in a volatile organic solventf therefor to providea viscous liquid adhesive composition, said phenol-aldehyde .resin consisting of thealkaline catalyzed condensation product yof: an aldel'iyde .of the classvconsisting of formaldehyde and acetaly dehyde anda monohydric phenolhavingonly twoparticularly reaction favorable positions, in vthe molecule and rsubstituted only` in the para position by a side .chain radical fromthe group consisting of alkyl andaryl hydrocarbon radicals containing at least four carbon atoms, the aldehyde being present in excess of a 1:.1` molecular ratio in relation to said phenol, said v.phenol aldehyde 'resin beingpresent to the; extent by weight ofmore.

than halfthat of the polychloroprene, but not to a greater extent thanl twice that of said polychloroprene; the said adhesivecement composition, upon application at ordina-ryroom temperature -as `a film .or coatinggto a. smooth metal surface and attachment of alfabric sheeting =thereto, willy at iirst .develop bond strength at .approximatelythe same rate as `an ordinary-solvent type reclaimed rubber,l limedrosi-n cement which has equal'paits of reclaimed rubber and.'limed'srosin,v

and Iafter three fdayswat. room temperature will have `developed a bond strength far greater thanV that o-f such reclaimed rubber, .limedrosin cement, and of the order of twice that of coatingsof saidY reclaimedrubber, limed rosin cement.

2. A solvent type adhesive cement composition which is resistant to gelation in solution during storage, .and upon application asa coating to impervious'snrooth metal surfaces forms a strongly adherent film of high internal strength on mere evaporation of solvent and Abrief yageing at normal room temperatures, said composition comprising a uniform blend of polyehloroprene and aphenolaldehyde resin,'said blend `being dissolved in a volatile organic solvent therefor lto provide a viscous liquid adhesive compositiomsaid phenol, aldehyde resin consisting of the alkaline catalyzed condensation product of formaldehyde and a monohydric phenol having only ytwo particularly reaction favorable positions instheimoleculeland substituted only inthe paralpos'ition b-yiasside chain lradical fromthe group consisting'of alkyl and aryl hydrocarbon radicals containing 4-8 carbon atoms, the mol proportion of the formaldehyd'e tothe said phenol being withinVv therange o-f approximately 1.'2:1'-up to 1.6:1;the conden. sation reaction between saidA phenol and'frm'aldehyde being carried to a point so as to provide a phenol aldehyde resin which is a solid at room temperature and has a melting point, when first heated, substantially above room temperatures but nc-t greater than about 180 F., said phenol aldehyde resin being present within the range of 65-85 `parts,by weight, to 10o partsfof saidpoly-l chloroprene, `thel said adhesive cement composition, upon application at ordinary room temperature as a film or coating to a smooth metal sur-l f sistant to gelation in solution during storage-and upon application as a coating to impervious metal surfaces and the like forms a. strongly adherent film of high internal strengthen evaporation of solvent and brief ageing at normalroom temperature, said composition comprising a uniform blend of polymerized. chloroprenev and `a phenol-aldehyde resin, vsaid phenolealdehyde vresin being va solid Vat room Atemperatures, andbeing composed substantially .completely .o-f 'the valkaline-.catalyzed partial condensation product of para-tertiarybutyl phenol and formaldehyde, said formaldehyde being in excess of equimolecular proportions with. said phenol, said phenol-aldehyde resin being present in the range of 55-'150 parts-by weight thereof to parts by weight of said polymerized chloroprene, said uniform blend of polychloroprene Vand resin being dissolved in a volatile aromatic hydrocarbon solvent ,to-provide a viscous liquid adhesive composition.

4. An adhesivecement composition which is re,- sistant to gela-tion in solution during storage and Aupon applicationas a coating-to `impervious metal surfaces and the like forms astrongly adherent nlm ofhigh internalstrength on evaporation of solvent and brief ageing at normal `room temperature, said composition comprising a. uniform blend offpolymerized chloroprene and a phenol-k aldehyde resin, said phenol-aldehyde resin being asolid at room temperatures and beingY composed 1 substantiallycompletely of ythe alkaline-'catalyzed partial condensation product lof para-'tertiaryamyl phenol and formaldehyde, said formaldehyderbeing in excess of equimolecular proportions with said phenol, said iphenol-aldeh-yde resin be-j ing present in the range-of 55-150 parts by Aweight thereof to 100 ,parts by Weightcf said polymerized chloroprene, saiduniform blend of polychloro-v prene -andresin lbeing dissolved in .agvolatile 4aromatic hydrocarbon solventl to provide a 4viscous liquid adhesive com-position.

5. An adhesive cementrcomposition which is resistant to, gela-tion in solution during storage and upon application asa coating to impervious metal surfaces andthe like forms a strongly adherent film of 'high internal strength on evap-` oration of solvent andv brief ageing at'normal room temperature, said composition comprising a uniform blend of polymerized chloroprene and a phenol-aldehyde resin, said phenol-aldehyde resin being a solid at room temperatures and being composed substantially completelyof the alkaline-catalyzed 'partial condensation product of para-phenyl phenol andformaldehyde, said formaldehyde being Iin excess of equimolecular proportions with said phenol, said phenol-aldehyde resin being present in the range of 55-150 parts by weight thereof to 100 parts by weight of said polymerized chloroprene, said uniform blend of polyohloroprene and resin being dissolved in a volatile aromatic hydrocarbon solvent to provide a viscous liquid adhesive composition.

6. An adhesive cement composition which is resistant to gelation in solution during storage, and upon application as ai coating to impervious metal surfaces and the like forms a strongly adherent film of high internal strength on evaporation of solvent and brief aging at normal room temperature, said composition comprising a. u'niform blend of polymerized chloroprene and an oil-soluble, heat-hardening phenol-aldehyde resin, said phenol-aldehyde resin being present in excess of one-half that of said polychloroprene, by Weight, but not being present in greater weight proportion than approximately that of said polychloroprene, said phenol-aldehyde resin consisting substantially completely of the condensation reaction product of formaldehyde and a substituted phenol to provide a resinwhich is a solid at room temperatures and which is compatible with the polychloroprene, said phenol being susbtituted in the para position by a side chain radical from the group consisting of alkyl and aryl hydrocarbon radicals, said formaldehyde being present in excess of equimolecular proportions with said phenol, said uniform blend of polymerized chloroprene and phenol-aldehyde resin being dissolved ina Volatile, aromatic hydrocarbon solvent to provide a viscous liquid adhesive composition.

7. In a mineral coated sheet article having a coating of mineral grains bonded to a flexible backing and having a rigid supporting means secured to the other side of said backing, a resilient bond between the supporting means and the mineral coated sheet containing as an essentiail ingredient a substantial proportion of a mixture of polychloroprene and an oil-soluble heat-hardening phenol-aldehyde resin, said phenol-aldehyde resin being present in excess of one-half that of said polychloroprene, by weight, but not being Ypresent in greater Weight proportion than approximately that of said polychloroprene, said phenol-a-ldehyde resin consisting substantially completely of the condensation reaction product of formaldehyde and asubstituted phenol to provide a resin which is a solid at room temperatures and which is compatible with the polychloroprene.

8. A structure comprising a fibrous sheet having mineral grains bonded thereto, the surface of said fibrous sheet opposite from the one carrying said mineral grains being bonded to a metal surface by a resilient bond consisting of the dried residue of a smooth Viscous'solvent type cement comprising a blend of polychloroprene and a phenol-aldehyde resin, the phenol-aldehyde resin being an oil-soluble, heat-reactive condensation product of formaldehyde with a phenol substituted in the para position with a tertiary-butyl radical, the phenol-aldehyde resin being present in an amount by weight in excess of one-half that of said polychloroprene but not to a greater extent than approximately that of said polychloroprene.

9. An adhesive bonding composition capable of producing a firm bond to a smooth metal surface, comprising a `uniform blend of polymerized chloroprene and an oil-soluble, heat-hardening, normally solid phenol-aldehyde resin, said blend being dissolved in a volatile organic solvent therefor 12 to provide a viscous liquid adhesive composition. said phenol-aldehyde resin being present in excess of one-half thatof said polychloroprene, by Weight, but. not being present in greater weight proportion than 150 parts thereof to 100 parts of said polychloroprene, said phenol-aldehyde resin consisting substantially completely of the condensation reaction product of formaldehyde and a substituted phenol to provide a resin which is a vsolid at room temperatures and -which is compatible with the polychloroprene, said phenol being substituted in the parav position by a side chain radical from the group consisting of alkyl and aryl hydrocarbon radicals" containing at least four carbon atoms, said .formaldehyde being present in excess of equimolecular proportions with said phenol, and saiduniform blend of polymerized chloroprene andphenol-aldehyde resin being of such character as to` provide a high-strength adhesive bond.

10. An adhesive bonding composition capable ofv producing a rm bond tosmooth metal surfaces, comprising a uniform blend of polymerized chloroprene' and phenol-aldehyde resin, said blend being dissolved in a volatile organic solvent therefor to provide a viscous liquid adhesive composition, said phenol-aldehyde resin being the condensation product of formaldehyde and a monohydric phenol having only two particularly reaction favorable positions in the molecule and substituted only in the para position by a nonolenic organic side chain radical from the group consisting of alkyl and'aryl hydrocarbon radicals having 4-8 carbon atoms, the aldehyde being employed in mol proportion in relation to said phenol in the range from 1:1 to 2:1, the condensation reaction between the said phenol and aldehyde' being carried far enough to provide a phenol-aldehyde resin having a temporary softening' point substantially above room temperatures but not greater than about 180 F., said phenol-aldehyde resin being present to the extent by weight of 60-90 parts to 100 parts of said polychloroprene, and said uniform blend of polychloroprene and phenol-aldehyde resin being of 'such character as to provide a high-strength adhesive bond.

ANDREW FARLEY THOMSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,931,309 Thompson Oct. 17, 1933 1,967,863 Collins et al July 24, 1934 2,122,691 yKuzmick et al. July 5, 1938 2,211,048 Bitterich Aug. 13, 1940 2,323,130 Harvey June 29, 1943 2,337,424 Stoner Dec. 21, 1943 2,394,375 Gross Feb. 5, 1946 2,430,987 Lindner etal Nov. 18, 1947 2,448,985 Kuzmick et al Sept. 7, 1948 OTHER REFERENCES Wakeman, The Chemistry of Commercial Plastics, pages 163 and 164, pub. 1947 by Reinholdlub. Corp., N. Y. 

1. A SOLVENT TYPE ADHESIVE CEMENT COMPOSITION WHICH IS RESISTANT TO GELATION IN SOLUTION DURING STORAGE, AND UPON APPLICATION AS A COATING TO IMPERVIOUS SMOOTH METAL SURFACES FORMS A STRONGLY ADHERENT FILM OF HIGH INTERNAL STRENGTH ON MERE EVAPORATION OF SOLVENT AND BRIEF AGEING AT NORMAL ROOM TEMPERATURES, SAID COMPOSITION COMPRISING A UNIFORM BLEND OF POLYCHLOROPRENE AND A NORMALLY SOLID PHENOL-ALDEHYDE RESIN, SAID BLEND BEING DISSOLVED IN A VOLATILE ORGANIC SOLVENT THEREFOR TO PROVIDE A VISCOUS LIQUID ADHESIVE COMPOSITION, SAID PHENOL-ALDEHYDE RESIN CONSISTING OF THE ALKALINE CATALYZED CONDENSATION PRODUCT OF AN ALDEHYDE OF THE CLASS CONSISTING OF FORMALDEHYDE AND ACETALDEHYDE AND A MONOHYDRIC PHENOL HAVING ONLY TWO PARTICULARLY REACTION FAVORABLE POSITIONS IN THE MOLECULE AND SUBSTITUTED ONLY IN THE PARA POSITION BY A SIDE CHAIN RADICAL FROM THE GROUP CONSISTING OF ALKYL AND ARYL HYDROCARBON RADICALS CONTAINING AT LEAST FOUR CARBON ATOMS, THE ALDEHYDE BEING PRESENT IN EXCESS OF A 1:1 MOLECULAR RATIO IN RELATION TO SAID PHENOL, SAID PHENOL ALDEHYDE RESIN BEING PRESENT TO THE EXTENT BY WEIGHT OF MORE THAN HALF THAT OF THE POLYCHLOROPRENE BUT NOT TO A GREATER EXTENT THAN TWICE THAT OF SAID POLYCHLOROPRENE; THE SAID ADHESIVE CEMENT COMPOSITION, UPON APPLICATION AT ORDINARY ROOM TEMPERATURE AS A FILM OR COATING TO A SMOOTH METAL SURFACE AND ATTACHMENT OF A FABRIC SHEETING THERETO, WILL AT FIRST DEVELOP BOND STRENGTH AT APPROXIMATELY THE SAME RATE AS AN ORDINARY SOLVENT TYPE RECLAIMED RUBBER, LIMED ROSIN CEMENT WHICH HAS EQUAL PARTS OF RECLAIMED RUBBER AND LIMED ROSIN, AND AFTER THREE DAYS AT ROOM TEMPERATURE WILL HAVE DEVELOPED A BOND STRENGTH FAR GREATER THAN THAT OF SUCH RECLAIMED RUBBER, LIMED ROSIN CEMENT AND OF THE ORDER OF TWICE THAT OF COATINGS OF SAID RECLAIMED RUBBER, LIMED ROSIN CEMENT. 